Distributor Question Mondial 3.2 | FerrariChat

Distributor Question Mondial 3.2

Discussion in 'Mondial' started by moysiuan, Nov 26, 2018.

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  1. moysiuan

    moysiuan F1 Rookie
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    At rest, when you take the distributor cap off on the rear bank, the rotor would be pointing towards one of the spark plug wires when the cap is one. Let's say its pointing at the cylinder 1 on the rear bank. If one then looks at the front bank, where should the rotor be pointing? It looks like the rotor can be mounted more than one way, as the triangle of three screws would allow that (or does it only mount one way?).

    I ask as I changed out the caps, wires/extenders, and the car is running poorly, clouds of fuel smelling smoke so obviously I did something wrong relating to ignition. I am wondering if I mis installed a rotor pointing out of sync. Yes I should have been careful to make sure I put the rotor back exactly in the way the old one was on, but these things are tricky to access, and I should have taken a picture to ensure no error, but did not.

    I have inspected things carefully, and nothing is obviously wrong, but maybe I put a wire in the wrong hole of a cap, one of the carbon button springs was hard to get back into its hole, maybe the coil connection is not as it should be, etc. But I want to go to first principles and make sure I have the firing orders correct, wires in the holes they should be in and the rotors pointing where they should.

    If anyone can share some perspective on this ignition system, that would be appreciated.

    (That front bank cap 8mm bottom screw on the cap is no fun to get at; and those rotor screws won"t allow a 7mm socket, and the lower ones also hard to get at with a short 7mm wrench. How did dealers get at these things, it took me a lot of fuss to do this this time around? Take whoel engine out? :) )
     
  2. mike32

    mike32 F1 Veteran

    May 13, 2016
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    You should be able to work it out from the firing order, just be sure to turn the crank the correct way if you are following the rotor arms motions
     
  3. spicedriver

    spicedriver F1 Rookie

    Feb 1, 2011
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    If you are turning the motor from the damper bolt, it's clockwise. I think 32 mm. Don't turn the motor backwards. You can also bump the starter to get the rotors in a better position to be removed. Do the front bank from the interior access panel. You may need to remove a bracket on the valve cover to get your hand through. Looking at the OEM cap from the top with the wire holes pointing downward, 1 bottom left, 3 top left, 4 top right, 2 bottom right. Corresponding numbers are on the valve covers. OEM rotor bolts may be rusted and difficult to remove. Careful not to strip those. Firing order 15374826. The motor should be able to run on one bank at a time by removing either coil wire. That may help to locate the problem bank.

    You can check to see if the wires are connected right by removing the cap and measuring the resistance between the electrodes in the cap, and the ends of the wires. You should have around 13K for new wires. That's 13,000 ohms. If you are getting an open circuit measurement, that wire is not connected.
     
  4. moysiuan

    moysiuan F1 Rookie
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    Excellent information, thank you.
     
  5. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
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    #5 Steve Magnusson, Nov 27, 2018
    Last edited: Nov 27, 2018
    The distributor rotor only mounts in one way - the screw pattern is not symmetric (by a small amount).

    When the 1-4 bank rotor is pointing at the #1 cyl terminal in the cap (#1 cylinder fires), the 5-8 bank rotor would be midway between the #6 and #5 terminal in the cap (moving to the #5 cyl terminal with another 90 deg of crank rotation = 45 deg of distributor rotor rotation).

    Don't forget to consider the action of the timing gears -- the crankshaft rotates CW as viewed at the snout/damper end as spicedriver posted, but the distributor rotors also rotate CW as viewed from the clutch end due to the timing gears adding a reversal.
     
  6. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
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    Agree that open circuit is a bad thing, but I've got the stock F spark plug wires as ~700 ohms/foot (so even the longest wire would only be about ~2K Ohms).
     
  7. spicedriver

    spicedriver F1 Rookie

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    #7 spicedriver, Nov 27, 2018
    Last edited: Nov 27, 2018
    To clarify, I used Accel 7mm suppression wires, which fit just right into the original outer sleeves. Cost around $20. These work well. Other brands of suppression wires should also work.

    The original Cavis wire is quite a bit more. New OEM assemblies are around $250/bank.

    https://www.midwest-bayless.com/FIAT-124SC-0_p-22962-spark-plug-wire-7mm-black-carbonwire-core-16-ft-roll-oe-cavis.aspx

    Perhaps the OP can measure his wire assemblies and post here.
     
  8. moysiuan

    moysiuan F1 Rookie
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    I am getting betwween about 900 and 1,200 ohms on the old wires. The coil wire measured 30,000 ohms, measured a few times, not sure what that's all about. I think the wires I am changing out were Cavis, bought from Eurospares 10 years plus ago. The new wires are Kingsborne. Will have to take everything apart and test each wire and connection to get the bottom of this. Will wait a couple days for my scraped hands to heal before redoing the job, before I report back.

    Great to knwo that I did not botch up the rotor placement. The new presumable reproduction rotors when rested on a flat surface are about 1mm shorter than the ones on there (which are Marelli). I think they will still match up with the cap contact points, but was surprised they were not completely identical. Can't rememeber the supplier, but they were the correct part numbers so I presume ther is some variation in the reproductions out there.

    To be comprehensive, what is the extender ohms should I expect? Maybe the repro quality control is not what it should be, so would be good to ruleout any problem with the new extenders.

    Again, thank you for such useful information.
     
  9. mike32

    mike32 F1 Veteran

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    I think i have 1 new OEM rotor arms around here somewhere from my mondial days
     
  10. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
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    Jan 11, 2001
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    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    #10 Steve Magnusson, Nov 28, 2018
    Last edited: Nov 28, 2018
    moysiuan likes this.
  11. spicedriver

    spicedriver F1 Rookie

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    #11 spicedriver, Nov 28, 2018
    Last edited: Nov 28, 2018
    Extenders should be zero ohms as stated. The way they fail is the insulation breaks down, and you get a little pinhole where it arcs to the head. You can see a little black mark on the extender, and you can also see on the head where it arcs to.

    It's probably best to change everything at one time. Coil wires, caps, rotors, extenders, plugs. I picked up a set of extenders from Superformance which work well, and look very much like the originals.

    http://www.superformance.co.uk/mondial/ignition.html
     
  12. moysiuan

    moysiuan F1 Rookie
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    Yes, I am changing all the items noted, I last did it 10 years ago, don"t recall it being as hard, maybe crouching the back seat area has just gotten harder for me 10 years on! Makes me want to rip out the folding seat back cushion, how is that thing actually attached?

    So here is what happened. Removed the caps/wires/extenders from both banks and tested each lead to the cap. Consistent measurement, including the coil wire at about 1,000ohms +- a couple hundred and less on the shorter leads as expected. Except for one wire, which did not read at all. Looks like the piercer screw in the cap did not in fact pierce, the red silicone insultation cover must have made me feel like I had it in far enough but I did not. So that should be it. Extenders are new, but checked them anyways, a couple of ohms. Will check rotors just be sure, then crawl back there and put it together. One last question, the carbon button protrudes about 4mm out of the cap, and springs in and out freely. Is this about what it should be, the spring did not go in so easily, so I am not sure if I over compressed it and perhaps it does not have sufficient travel? My guess is it is ok, but would feel better if others have the same amount extended to ride the rotor.
     
  13. spicedriver

    spicedriver F1 Rookie

    Feb 1, 2011
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    I keep my old parts in a box. The OEM cap button sticks out 10mm.

    Where did you get your caps ? I got Superformance caps which look really nice, but none of the wire holes were deep enough to get the conductor pin on the wire. I had to drill them out with a 3/8 bit. Careful not to drill all the way through !
     
  14. moysiuan

    moysiuan F1 Rookie
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    I think they were Superformance, I bought them some years ago knowing I would need them eventually. I think the hole was a bit shallow, hopefully they have enough of a grip to stay put, I would have been histant to do drill, but these pattern parts are often not quite exact, that I have learned over the years.. They are reproductions, the ones on the car at that time were still the original Marelli's. 10mm of button, that pretty much the whole button sticking out!
     
  15. moysiuan

    moysiuan F1 Rookie
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    Everything running perfecrtly now, thank you for all the technical support.

    Onto the next winter project, which will be replacing the drivers side differnetial seal. Should have done it when I did the CV boots two years ago, but there was no leak then, now its flinging oil onto the header, not really too bad but I am a perfectionist, so onwards...There is lots of technical perspective in the Birdman tutorial and other threads, but will post if anything get's confusing. Is there anything blazingly obvious I should know about this project from those who have done it before? eg. Is the big bolt impossible to get off without an impact wrench (which I don't think there is room with the engine in for an impact wrench). Do I need to drain the differential, or is the oil level below the seal/carrier/diff shaft? That sort of thing.
     

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